1. Field of the Invention
The present invention relates to a system for controlling a process of restoration from a failure of control data used in computer equipment and provided in a queue structure. The computer equipment which controls a control data group having a queue structure connected by pointers. The system according to the present invention can be used for restoring the queue structure of control data when a failure occurs in the queue structure.
2. Description of the Related Art
A queue is one of the structural data types for control data for computer programs. The queue type data structure is used to provide a sequence of operations arranged to form a data queue. In operation of the queue type data structure, different kinds of operations are provided, for example NEW, FRONT, DELETE, ADD, ISNEW, etc.
In general, in the handling of control data, identifiers are provided in the control data, the control data are chained by forward and backward pointers, and the first group of control data and the last group of control data are connected by pointers to a main control table.
In the prior art, when a failure occurs in the control data in a queue structure and the queue structure is resultingly destroyed, the control data queue is inspected along the forward direction represented by a sequence of the forward queue pointers, as well as along the backward direction represented by a sequence of the backward queue pointers to detect the location of the failure. Based on the detection of the failure, connections of the control data are changed. By changing the connections, the control data are connected by forward queue pointers and backward queue pointers, and accordingly the queue structure is restored at least for the time being. In the conventional restoration process, however there is a problem that, the inspection of the queue pointer is interrupted at the time when the failed control data is found, and accordingly it happens that the control data which has not failed, i.e., the normal control data which neighbors the failed control data, is excluded from the queue structure causing the excluded control data to be lost.
Also in the conventional restoration process, there is a problem that a control data identifier is provided in the control data, and therefore, once the identifier itself is destroyed, it becomes impossible to identify the failed control data.